Drilling tool



Oct. 3, 1944.

T. HAYES DRILLING TOOL Filed July 2, 1942 I Thunms L.Hu ye.5

Patented Oct. '3, 1944 UNITED STATES PATENT OFFICE (Granted under theact of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 2Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

This invention relates to a tool holder, more particularly a boring ordrilling attachment for controlling the depth of holes drilled inarticles, and specifically to an attachment for use in boring burstercharge cavities in shell noses where the depth of the cavity must beheld within close tolerance.

An object of this invention is to provide a drilling and boringattachment for use with a boring cutter to control the depth of a holebored by said cutter. Another object is to provide in such an attachmentmeans for holding a boring cutter and means whereby the attachment maybe chucked in a drill press or like machine. Another object of theinvention is to provide a simple attachment incorporating a cutting toolwhich has a shoulder relatively rotatable with respect to both the tooland driving machine, said shoulder serving as a stop for engagement withthe work to limit the penetration of the work by the cutting tool.

Other objects and advantages of the invention will be apparent from thefollowing description of a preferred embodiment thereof as shown in theaccompanying drawing in which:

Fig. 1 is a view in section of an attachment incorporating a tool,

Fig. 2 is a similar view of the attachment taken along the line 22ofFig. 1, and

Fig. 3 is a bottom plan view of the tool holding sleeve.

The attachment according to the invention includes a cutting-toolholder, means for attaching said holder to a boring machine, aworkengaging stop means, and complementary thrust bearing elementscarrying said tool holder and said stop means respectively.

Referring to the drawing, a holder for the cutting-tool is comprised ofa sleeve I and a shank 2 integrally united at 3 by mating threads. Acollar comprising a cylindrical member 4 and a retaining ring 5,surrounds the tool holder and provides, together with the tool holder,an inclosed annular space 6 housing a thrust bearing consisting of lowerand upper races I and 8, respectively, including ball bearings 9. Upperrace 8 bears against the lower surface I of the shank but not againstthe lower surface of retaining ring 5. Lower race I bears against thehorizontal inner surface I I of the bottom portion of the collar but notagainst any portion of the tool holder sleeve I. The collar serves as aworkengaging stop means, the under surface of the collar being adaptedto engage the upper surface of a piece of work being drilled, therebylimiting penetration of the tool into the work.

A tool I2 having cutting blade I3 and threaded tang I4 is inserted inthe tool holder, the shoulder 2| of the tool resting in the slot 22 ofthe sleeve I. Lock nuts I5 and I6 secure the tool in the holder at thedesired setting, nut I5 being backed against the tool holder shank andnut I6 being screwed in the opposite direction against the top of thetool holder sleeve, whereby the tool is held rigidly in the holder. Thusis provided means for adjusting and locking the tool in the holder, nutI6 functioning as an adjusting nut and nut I5 functioning as a lockingnut.

The tool holder shank is provided. with an aperture I8 through which thelock nuts may be inserted and adjusted.

The tool holder shank is provided further with an extension I! forengagement in the chuck of a conventional rotary driving machine such asa drill press. Of course, alternatively, the tool holder may be fixed,as in the tail stock of a lathe, and the work may be rotated relativelyto it, as by the lathe head.

The attachment is assembled by screwing the sleeve I into the shank 2.Thrust bearing I, 8, 9 is placed inside the collar as shown. Theassembled tool holder next is inserted downwardly into the lower portion4 of the collar until the shoulder II) of the shank rests against theupper race 8 of the thrust bearing. Retaining ring 5 then is placed overthe lower portion of the collar and is secured in position by screws I9.

The lower portion of the collar preferably is provided with a groove 20containing suitable packing material to seal the annular bearing spaceagainst admission of damaging particles of foreign material, such aschips and the like, and also to retain lubricant within the bearingspace.

In operation, a boring tool I2 is assembled to the attachment with itslower cutting surface positioned the desired distance below the lowersurface of the collar. The attachment, mounting the tool, is then fixedin a drill press or the like and the hole is bored in the work inconventional manner. When the desired depth of hole has been made thelower surface of the collar comes in contact with the upper surface ofthe work and prevents the tool from going any deeper. Thrust forcestending to drive the tool beyond the desired depth are absorbed in thethrust bearing, the collar remaining stationary against the work and thetool holder and tool rotating together upon the bearing within thecollar.

It will be seen that this invention provides a useful and simpleattachment for controlling the depth of drilled holes. The embodimentherein described is intended to be merely illus trative of the inventionand not limitative thereof, the appended claims being definitive of thescope of the invention.

I claim:

1. A drilling attachment comprising a tool holder formed in part by asubstantially cylindrical sleeve having a bore therethrough for thereception of a tool provided with a threaded end portion and in part bya shank secured to said sleeve providing, in conjunction with saidsleeve, 2. chambered portion adjacent one end of said sleeve, said shankfurther providing aside opening for said chamber, a rotatable collardisposed about said tool holder, providing, with said holder, aninclosed annular space, a thrust bearing within said space comprisingcomplementary bearing elements, one of which elements bears solely onsaid collar and the other of which bears solely on said tool holder,whereby thrust forces tending to move said tool holder longitudinallywith respect to said collar are absorbed in said bearing, and means insaid chambered portion adjustable through said opening cooperating withthe threaded end portion of a tool received therein, with a wall of saidchambered portion and with said sleeve to adjust and lock the toolrelative to said sleeve and shank.

2. The drilling attachment of claim 1, characterized in that theadjusting and locking means for the tool comprises an adjusting nut anda locking nut.

THOMAS L. HAYES.

